Kiwi detainees at Christmas Island stepped in to protect a refugee from being assaulted by "heavy-handed" guards, sparking the riots which saw the guards abandon the facility, one detainee claimed.
It is understood that riots began in the early hours of yesterday morning (local time) after prisoners learned of the death of an Iranian Kurdish refugee who escaped the centre two days ago.
Fires are burning, walls have been smashed in, the lights have been turned off and there are no guards in sight, detainees say.
Gas canisters have reportedly been unsuccessfully used in an attempt to quell the unrest.
New Zealand detainee Lester Hohua said the rioting at Christmas Island Immigration Detention Centre had been brewing.
Over-crowding and alleged assaults by the emergency response team (ERT) had put the detainees, including about 40 New Zealanders, at "breaking point", he said.
"This was always going to happen," Mr Hohua told NZME News Service.
"You can only back someone into a corner so much."
The unrest began with upset refugees asking officials what happened to refugee Fazel Chegeni, whose body was found on Sunday following his escape from the detention centre on Friday.
"They just wanted straight-forward answers, and weren't given straight-forward answers," Mr Hohua said.
The hated ERT were sent in, he claimed, and jostled with the refugees.
Mr Hohua claims that one ERT member challenged one refugee to a "one on one" fight.
"That's when us 501s [convicted criminals with cancelled visas] got involved," he said.
"You can't f***ing do that. Who are you? You know.
"We didn't get involved, as in, throw any punches, but we made sure that he wasn't going to touch the refugee, or any of them were going to touch the refugee.
"Refugees don't fight. Refugees just yell and scream and argue and get beaten up for it.
"Everything was about protecting each other, saving the refugees from getting the bash. We're sticking up for our brothers.
"New Zealanders, just 501s in general, doesn't matter what country you are from, are being beaten to a pulp, sent to hospital ... we're sick of it.
"People are scared by it. That's why you had the reaction you had last night."
Only a "small handful" of detainees then began rioting, Mr Hohua said.
Most of the detainees held a "peaceful protest" by sitting down in the middle of the field.
Others just went back to their compound, Mr Hohua said.
"Not everybody was being a f***ing idiot."
The ERT have a reputation with detainees as having "heavy hands", Mr Hohua claimed.
He said assaults were commonplace.
"They beat people to a pulp, break bones, put people in hospital, knock teeth out," he said.
"They rock up at 3-4am, whip your arse out of bed, throw you to the ground, face to the floor, hands behind your back, and rip-tie you. And we've done nothing wrong."
At 5.30pm (NZ time), Hohua said there were still no guards at the facility.
There were fears the guards would return with guns, he said.
"They're driving around the perimeter. We've had word that they are here and are probably gearing up," he said.
"We're all in back in our compounds, sitting and waiting."
Hohua was not aware of any of the detainees having weapons.
A spokesman from the Australian Department of Immigration and Border Protection confirmed the situation was ongoing this morning.
"The department can confirm a disturbance at Christmas Island Immigration Detention Centre," the spokesman said.
"The department and its service providers are working together to resolve the situation."
The spokesman said some reports of damage at the centre had been received but were yet to be confirmed.
There had been no reports of injuries and any criminal offences would be referred to the police, the spokesman said.
"The Department will not speculate on the motivations of those involved.
"It would not be appropriate to make further detailed comments on matters that are subject to ongoing operations."
Labour corrections spokesman Kelvin Davis said the situation "basically just went mad" after one detainee was allegedly assaulted by a guard.
Mr Davis visited the island about 10 days ago and is in contact with a number of detainees in the centre.
"The guards have disappeared at this stage, they can't see anything of them. There's concerns when they come back they'll come back with force possibly even with guns," he told NZME News Service.
"They've asked me to try and get people over there so that when all the dust has settled down there'll be witnesses to the injuries they believe they're going to incur. They're scared."
Mr Davis said the next step was to get officials over to Christmas Island to check on the New Zealand detainees.
It is believed there are about 40 Kiwis currently at the centre.
Mr Davis previously told the Herald that detainees were almost at "breaking point" and were considering rioting in late October.
"They said, 'To hell with it, if nobody's going to listen.' Basically, there's a sense of hopelessness, despair and uncertainty. There's no sentence, there's no end date for them," he told the Herald.
A law change in Australia means foreign nationals automatically have their visas revoked if they have convictions with penalties totalling more than 12 months in prison.
The Herald reported in October about 1000 people are expected to be deported back to New Zealand under the policy and about 240 are in detention centres awaiting deportation or for their appeals to be heard.
Amnesty International is calling for the New Zealand Government to speak out against Australia's "abysmal human rights record", in light of the riot.
Australia is about to undergo its Universal Periodic Review -- an analysis of each UN member country's human rights record every four years -- which makes the timing even more fitting, Amnesty International New Zealand spokeswoman Meg de Ronde said.
"Australia has an appalling track record for its policies around asylum seekers, and current news reports on the incidents at the detention centre on Christmas Island are not only deeply concerning, but are a prime example of why New Zealand can no longer stay silent on Australia's refugee and asylum seeker policies," she said.
New Zealand should push Australia to take all children, families and traumatised people out of detention centres and put an end to indefinite periods of detention, she said.
The calls come after Amnesty International supporters gathered outside the Australian Consulate in Auckland on October 30 to protest an incident in May where Australian officials turned around a boat with asylum seekers apparently attempting to get to New Zealand.
Hohua said the unrest was a spontaneous reaction to the detainees' treatment.
He hoped that "something positive" would come out of it.
Another protest outside the Australian Consulate in Auckland is planned for 1pm on Wednesday.